scholarly journals A model for gauged skyrmions with low binding energies

2021 ◽  
Author(s):  
Josh Cork ◽  
Derek Harland ◽  
Thomas Winyard
Keyword(s):  
Numerical Simulation ◽  
Dipole Moment ◽  
Lower Bound ◽  
Boundary Conditions ◽  
Magnetic Dipole Moment ◽  
Binding Energies ◽  
Maxwell Theory ◽  
Yang Mills ◽  
Energy Bounds ◽  
Experimental Values

Abstract We consider gauged skyrmions with boundary conditions which break the gauge from SU(2) to U(1) in models derived from Yang–Mills theory. After deriving general topological energy bounds, we approximate charge 1 energy minimisers using KvBLL calorons with non-trivial asymptotic holonomy, use them to calibrate the model to optimise the ratio of energy to lower bound, and compare them with solutions to full numerical simulation. Skyrmions from calorons with non-trivial asymptotic holonomy exhibit a non-zero magnetic dipole moment, which we calculate explicitly, and compare with experimental values for the proton and the neutron. We thus propose a way to develop a physically realistic Skyrme–Maxwell theory, with the potential for exhibiting low binding energies.

scholarly journals Pseudospin versus magnetic dipole moment ordering in the isosceles triangular lattice material K3Er(VO4)2

2020 ◽  
Vol 102 (10) ◽  
Author(s):  
Danielle R. Yahne ◽  
Liurukara D. Sanjeewa ◽  
Athena S. Sefat ◽  
Bradley S. Stadelman ◽  
Joseph W. Kolis ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Magnetic Dipole ◽  
Triangular Lattice ◽  
Magnetic Dipole Moment ◽  
Lattice Material

Shape Optimization and Strength Evaluation of Metal Welded Bellows Wave of Mechanical Seal

2008 ◽  
Vol 33-37 ◽  
pp. 1377-1382 ◽  
Author(s):  
Halida Musha ◽  
Mamtimin Gheni ◽  
Buhalqam
Keyword(s):  
Numerical Simulation ◽  
Bone Mass ◽  
Boundary Conditions ◽  
Shape Optimization ◽  
Reaction Diffusion ◽  
Mechanical Seal ◽  
Forming Process ◽  
Strength Evaluation ◽  
Fem Method ◽  
Initial Load

In this paper, the iBone (Imitation Bone) model which is coupled with Turing reaction-diffusion system and FEM, is used. The numerical simulation of bone forming process by considering the osteoclasts and osteoblasts process are conducted. The bone mass is increased with increase of the initial load value, then fibula and femur bones are obtained respectively by keeping the required bone forming value. The new S shape wave of metal welded bellow of mechanical seal are designed based on the the optimization results through this method. The S shape and V shape both were analyzed with FEM method. The same boundary conditions were given for two types of wave. The results are shown that the stresses mainly concentrated on the welded area. It is interesting that the value of the stresses of the two types of wave basically same. However, compressibility of the two types of wave is very different at the same computation stage. The compressibility of S shape wave was higher than V shape.

scholarly journals Stellar activity and magnetic shielding

2009 ◽  
Vol 5 (S264) ◽  
pp. 385-394 ◽  
Author(s):  
J.-M. Grießmeier ◽  
M. Khodachenko ◽  
H. Lammer ◽  
J. L. Grenfell ◽  
A. Stadelmann ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Magnetic Dipole ◽  
Magnetic Dipole Moment ◽  
Direct Interaction ◽  
Planetary Atmosphere ◽  
Stellar Activity ◽  
Planetary Environment ◽  
Atmospheric Loss ◽  
Planetary Magnetic Field ◽  
Planetary Habitability

AbstractStellar activity has a particularly strong influence on planets at small orbital distances, such as close-in exoplanets. For such planets, we present two extreme cases of stellar variability, namely stellar coronal mass ejections and stellar wind, which both result in the planetary environment being variable on a timescale of billions of years. For both cases, direct interaction of the streaming plasma with the planetary atmosphere would entail servere consequences. In certain cases, however, the planetary atmosphere can be effectively shielded by a strong planetary magnetic field. The efficiency of this shielding is determined by the planetary magnetic dipole moment, which is difficult to constrain by either models or observations. We present different factors which influence the strength of the planetary magnetic dipole moment. Implications are discussed, including nonthermal atmospheric loss, atmospheric biomarkers, and planetary habitability.

Experimental and computed dipole moments in donor–bridge–acceptor systems with p-phenylene and p-carboranediyl bridges

2009 ◽  
Vol 74 (1) ◽  
pp. 131-146 ◽  
Author(s):  
Ladislav Drož ◽  
Mark A. Fox ◽  
Drahomír Hnyk ◽  
Paul J. Low ◽  
J. A. Hugh MacBride ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Dipole Moments ◽  
Electronic Effects ◽  
Electronic Interactions ◽  
Donor And Acceptor ◽  
Homo And Lumo ◽  
Pull Systems ◽  
The Difference ◽  
Experimental Values ◽  
2D And 3D

Dipole moments were measured for a series of substituted benzenes, biphenyls, terphenyls, C-monoaryl- and C,C′-diaryl-p-carboranes. For the donor–bridge–acceptor systems, Me2N–X–NO2, where X is 1,4-phenylene, biphenyl-4,4′-diyl, terphenyl and 1,4-C6H4-p-CB10H10C-1,4-C6H4, the measured interaction dipole moments are 1.36, 0.74, 0.51 and 0.00 D, respectively. The magnitude of the dipole moment reflects the ability of the bridge to transmit electronic effects between donor and acceptor groups. Thus, whilst the 1,4-phenylene bridges allow moderate electronic interactions between the remote groups, the p-carboranediyl unit is less efficient as a conduit for electronic effects. Averaged dipole moments computed at the DFT (B3LYP/6-31G*) level of theory from two distinct molecular conformers are in good agreement with the experimental values. Examination of the calculated electronic structures provides insight into the nature of the interactions between the donor and acceptor moieties through these 2D and 3D aromatic bridges. The most significant cooperative effect of the bridge on the dipole moment occurs in systems where there is some overlap between the HOMO and LUMO orbitals. This orbital overlap criterion may help to define the difference between “push-pull” systems in which electronic effects are mediated by the bridging moiety, and simpler systems in which the bridge acts as an electronically innocent spacer unit and through-space charge transfer/separation is dominant.

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